A hypervisor is the engine that runs virtual machines. It controls resource allocation, isolation, and performance, making virtualization and modern cloud infrastructure possible.
Two types of hypervisors Type 1 — Bare-metal
Runs directly on the hardware.
Examples: VMware ESXi, Microsoft Hyper-V (server edition), Xen.
Fast, stable, used in data centers.
Type 2 — Hosted
Runs on top of an existing operating system.
Examples: VirtualBox, VMware Workstation, Parallels.
Easier to install, good for personal use and development.